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mina [271]
3 years ago
11

What do you use to write on a blackboard? ​

Physics
2 answers:
Archy [21]3 years ago
6 0

Answer:

Chalk

Explanation:

please mark as brainliest

Elina [12.6K]3 years ago
4 0

Answer:

Chalk, expo markers. Why?

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What is the definition of physics
Stella [2.4K]

Answer:

the branch of science concerned with the nature and properties of matter and energy. The subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.

3 0
3 years ago
How much gas is there in 100cm3 of air?
sweet [91]
<span><em>78% = nitrogen</em>

<em>21% = oxygen</em>
</span>
<em>%1  = noble gases</em>
6 0
3 years ago
Read 2 more answers
A heavy ball with a weight of 150 N is hung from the ceiling of a lecture hall on a 4.1-m-long rope. The ball is pulled to one s
AlladinOne [14]

Answer:

The tension in the rope is 262.88 N

Explanation:

Given:

Weight W = 150 N

Length of rope r = 4.1 m

Initial speed of ball v = 5.5 \frac{m}{s}

For finding the tension in the rope,

First find the mass of rod,

mg = 150                          ( g = 9.8 \frac{m}{s^{2} } )

  m = \frac{150}{9.8}

  m = 15.3 kg

Tension in the rope is,

  T = mg + \frac{mv^{2} }{r}

  T = 150 + \frac{15.3 \times (5.5)^{2} }{4.1}

  T = 262.88 N

Therefore, the tension in the rope is 262.88 N

7 0
4 years ago
A mover loads a 100 kg box into the back of a moving truck by
hammer [34]

Explanation:

Mechanical Advantage (MA)

MA=d1d2=FoutFin ; d1 is the distance of effort, d2 is the distance the object is moved

7 0
3 years ago
Two lasers are shining on a double slit, with slit separation d. Laser 1 has a wavelength of d/20, whereas laser 2 has a wavelen
Marta_Voda [28]

Answer:

a) that laser 1 has the first interference closer to the central maximum

c) Δy = 0.64 m

Explanation:

The interference phenomenon is described by the expression

         d sin θ = m λ

Where d is the separation of the slits, λ the wavelength and m an integer that indicates the order of interference

For the separation of the lines we use trigonometry

        tan θ = sin θ / cos θ = y / x

In interference experiments the angle is very small

          tan θ = sin θ = y / x

         d y / x = m λ

a) and b) We apply the equation to the first laser

          λ = d / 20

          d y / x = m d / 20

          y = m x / 20

          y = 1 4.80 / 20

          y = 0.24 m

The second laser

        λ = d / 15

          d y / x = m d / 15

          y = m x / 15

          y = 0.32 m

We can see that laser 1 has the first interference closer to the central maximum

c) laser 1

They ask us for the second maximum m = 2

            y₂ = 2 4.8 / 20

            y₂ = 0.48 m

For laser 2 they ask us for the third minimum m = 3

In this case to have a minimum we must add half wavelength

         y₃ = (m + ½) x / 15

         m = 3

         y₃ = (3 + ½) 4.8 / 15

         y₃ = 1.12 m

        Δy = 1.12 - 0.48

        Δy = 0.64 m

4 0
3 years ago
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